Breather



Nov. 25, 1941.

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Nov. 25, 1941. s. x. WILLARD 2,264,107

BREATHER Filed Jan. 24, 1940 3 Sheets-Sheet 3 Patented Nov. 25, 1941 BREATHER Staples X. Willard, Chicago, 111., assignor to Vent Seal Company, Inc., a corporation of Georgia Application January 24, 1940, Serial No. 315,435

7 Claims.

This invention relates particularly to breathers adapted to permit gas to pass in and out of storage tanks, or the like, at desired pressures.

The primary object of the invention is to provide a breather, attractive in appearance and of comparatively small size which is capable of handling comparatively large volumes of gas at designed pressures. As devices of this character are frequently used on large storage tanks, which are much more capable of standing a high internal pressurethan a comparatively low external pressure, it is necessary to have a unit which will not permit air to be exhausted until the internal pressure is rather high, but will permit air to enter whenthere is a slight vacuum in the tank.

Another object of the invention is to prevent loss or carrying over from one compartment to another, th liquid which is used to seal the pipes.

A further object of the invention is to provide gas-Spreaders on, the lower end of the gas inlet pipes, so that the incoming gas will be divided up into comparatively small bubbles and be spread out through a large area of the liquid body which forms the seal.

Still another object of the invention is to arrange a series of liquid-seal chambers in communicating series so that there can be a reduction in the overall height of the device.

Another object of the invention is to provide a protective screen and hood for the vent to atmosphere on top of the container. The cover serves to protect the screen from snow, rain, and wind-home objects. It also permits the screen to be easily removed and cleaned and provides ready access to the filler plugs for maintaining a desired head of liquid in each 0! the various compartments.

The invention is illustrated in a preferred embodiment in the accompanying drawings, in which:

Figure 1 is a broken vertical sectional view of a breather embodying the invention; Figure 2, a fragmentary sectional view, taken as indicated at line 2 of Figure 1; Figure 3, a sectional view, taken as indicated at line 3 of Figure 1; Figure 4, a fragmentary sectional view of the top of the breather, taken at a slightly different angle from the view in Figure 1; and Figure 5, a sectional view, taken as indicated at line 5. of Figure 4. r

The devic illustrated is adapted to properly vent a tank having a flow of about five hundred gallons per minute. The outside dimensions of and six feet in height. Of course, the proportions may be varied considerably and these figures are mentioned merely to give a better understanding of the illustrations.

In the embodiment illustrated, a round, cylindrical container 6, having a bottom I, is supported on a centrally disposed breather pipe 8. The breather pipe and partition 9 divide the cross-sectional area of th main container into four chambers of substantially the same area. The chamber It] may be referred to as the low pressure chamber, as under vacuum conditions in the tank, to which the breather pipe 8 is attached, gas or air will be admitted through the pipe II. The high pressur chambers l2, l3, and M are connected in series, as will be ex-i plained below, and serve to permit gas to be discharged through the series when the internal pressure of the tank exceeds a desired pressure. Under these conditions air passes up through the pipe 8, through the top of the chamber l0 into the liquid-seal pipe l5 of the chamber l2, down through the spreader head I6, up through bailles I1 to the top of the chamber where it is conducted down through the next liquid-seal pipe, and in the same manner through the chambers 13 and H which are of similar construction to the chamber 12. As the internal parts, of the chambers l2, l3, and I4 are alike, similar reference numbers have been used.

As best shown in Figure 4, when the air leaves the chamber it, it passes up through a neck 18 and is free to be discharged to atmosphere through the fire screen l9 and under the cover 20. Assuming that each of the chambers l2, l3, and I4 are filled to maintain a head of twentyone inches, it will be understood that the heads are cumulative and accordingly a pressure of sixty-three inches will be required to permit air to be vented from the pipe 8 to atmosphere.

It may be noted that the bottoms 2| oi the series compartments l2, l3, and M are placed above the bottom of the container 1 and that the bottom of the chamber l0 communicates with a compartment in the bottom of the container which has the cross-sectional area of substantially the entire unit. While it is desirable to have a comparatively high head of oil in each of the series compartments to maintain a relatively high pressure, it is equally desirable in the low pressure compartment to maintain a low head of oil so that air can be admitted to the chamber I 0 when there is a vacuum of but a few ounces. Under these conditions, air may readily enter from the hood through the pipe H and spreader the unit are a little over two feet in diameter so as to bubble through a few inche of oil and after passing through the baiiies ll, enter a breather pipe I.

As the pipe II is longer than the combined heads of oil in the tanks I2, l3, and Il, pressure on the unit will merely force oil from the bottom of the container up through the pipe II. In the unit illustrated, the pipe is sixty-nine inches high. and at two pounds per square inch pressure, the oil will stand at approximately sixty-four inches. This gives a margin of five inches. or two and one-half ounces of pressure.

Two sets of baflles l I are provided on the upper part of each chamber. The purpose of these bailies is to remove entrained droplets of oil that may have been picked up by the air in bubbling through the liquid-seal. The baffles each have a series of blades 22 which are sandwiched between plates 23 and 24 and gradually converge towards the center of the chamber, around the pipes it. As best shown in Figure 2, the air passage between the blades is curved and gradually reduced in cross-sectional area so that the air is given increased velocity as it turns in towards the pipe I! to escape through the opening 25 in the upper plate 23. The momentum of the droplets in turning causes them to impinge against the blade and thereby become separated from the gas. Each of the bafiles is provided with a centralbasin 26 to catch the oil collecting on the blades 22 and these basins drain back into the body of oil in the lower portion of the chamber throughpipes 21. By conducting the oil back in this manner there is less opportunity for the air to again pick up the oil, The action of the upper baiiles is the same as the lower ones and serves to further reduce the amount of oil that might otherwise be carried along.

The spreaders l6 are preferably enlarged housings on the lower ends of the liquid-seal pipes and are provided with a series of diagonal slots 28 through which air may escape in small bubbles. The spreaders divide the bubbles out over a larger area and more effective use of the oil is thus made. That is, there is less turbulence and less oil is picked up by the air.

It may be noted that by arranging the three pressure chambers in series, even it a certain amount of oil is carried over from one chamber to another, the total head remains substantially the same. However, it is desirable to check the oil levels from time to time. Each of the chambers is provided with a drain plug 29. Oil maybe added to the chamber 10 by removing the hood 2!! and pouring the oil through the pipe ll. Oil may be added togthe chamber H in like manner.

A pair of inlet plugs 30 are provided at the top of the container for admitting oil to thechambers l2 and I3.

Preferably, the cover 20 is dome-shaped and extends to the full diameter of the container so that there is little likelihood of snow entering and freezing, or icicles forming which might block the breather. It is provided with a supporting flange ll having keyhole slots to fit over studs 32 provided on the top of the container. The screen it may be fixed to the inside of the hood so that it may be readily removed therewith and washed occasionally so as not to interfere with the passage of air. q

With a device of substantially the size indicated, it is found that to maintain a pressure of two pounds per square inch, slightly over ten gallons of oil is required in each of the pressure compartments. To maintain a vacuum. a little less than six gallons is required for each half ounce of vacuum.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom for some modifications will be obvious to those skilled in the art.

I claim:

1. A breather for storage tanks, comprising: a container divided into a plurality of longitudi- 5 nally extending chambers adapted to hold bodies of liquid; one of said chambers having a liquidseal pipe disposed in said chamber so as to permit gas to pass through said container in one direction when the back pressure is slightly-below atmosphere, and to check passage of gas in the opposite direction except at relatively high pressure; and a communicating series of other cham- -bers in the container having liquid-seal pipes arranged so as to check the passage of gas back through the series and to permit the gas to pass through the container in the opposite direction, through the series. at a pressure somewhat below the pressure which would be required for gas to pass through the first chamber in that direction.

2. A device as specified in claim 1, in which each of the liquid-seal pipes is provided at its lower end with an enlarged, perforated, gasspreader head.

3. A device as specified in claim 1, in which each of the chambers is provided with curved ballles disposed so as to change the direction and increase the velocity of gas leaving the chambers and thereby scrub the gas substantially free of entrained liquid droplets.

4. A device as specified in claim 1, in which the container is round in cross-section. and is divided into four sections which form the chambers. y

5. In a device for the purpose set forth: a round cylindrical container divided into a plurality of longitudinally extending chambers adapted to hold separate bodies of liquid, each of said chambers having a liquid-seal pipe; and a centrally disposed breather pipe supporting said container and communicating with two of said chambers in parallel, one of said chambers being a low pressure inlet chamber with its liquid-seal pipe arranged to permit the fiow of gas back into the breather pipe when the pressure is slightly below atmosphere, and the other chamber being a high pressure exit chamber connected in series with the remaining chambers and having their liquid seal pipes disposed to permit gas to pass out of the container only when the pressure is substanou tially above atmosphere.

6. A device as specified in claim 5, in which the container is provided at its upper end with a vent to atmosphere, said vent being enclosed with a screen and housed in a dome-shaped removable 5 cover.

'7. A device as specified in claim 5, in which the bottom of the low pressure inlet chamber opens into a compartment whose cross-sectional area is substantially that of the entire container.

STAPLES x. WILLARD. 

